Several accessories for mobile stations are commercially available for implementing the hands-free function. Ericsson manufactures an accessory HPR-08 for a mobile station. The HPR-08 comprises two earpieces, a microphone and an FM radio module. A cord interconnects the earpieces, the microphone and the FM radio module. The FM radio module can be attached to the bottom connector of certain mobile telephone models (for example Ericsson T10). This allows the radio to be listened to via the earpieces. When a call comes in, the radio is automatically muted, and once the call has been answered (for example by pushing the yes button in the mobile telephone), the earpieces can be used for listening to the call and the microphone for talking.
The accessory HPM-10 for an Ericsson mobile station can also implement the hands-free function. The HPM-10 comprises two stereo earpieces, a microphone and an MP3 audio player. A cord comprising a button for answering a call interconnects the earpieces, the microphone and the MP3 player module. The MP3 player module can be fastened to the bottom connector of certain mobile telephone models (for example Ericsson T10). The MP3 player module is powered by the mobile telephone. This allows music to be listened to by the earpieces from the MP3 audio player. When a call comes in, the MP3 audio player is automatically muted, and the earpieces can be used for listening to the call and the microphone for talking once the call has been answered (for example by pushing the button on the cord).
U.S. Pat. No. 5,978,689 (FIG. 1) discloses an implementation that integrates an audio set and a radiotelephone into the same housing 10. The implementation also comprises earpieces 11, interconnected by a headband 12, and a microphone 13. A cord 14 can be used to connect the housing 10 and the earpiece/microphone combination 11 to 13. For this purpose, the housing 10 comprises a jack 15, with which a plug 16 at the end of the cord 14 mates. With the microphone 13 in an upper position, the earpieces 11 can be used for listening to an audio program from the audio device. When the microphone 13 is moved to a lower position, the earpieces 11 and the microphone 13 can be used for listening to a call and for talking.